1. Field of the Invention
The present invention relates to a substrate for integrated circuit (IC) package and more particularly, to a high density substrate for IC package.
2. Description of the Related Art
Following fast development of technology, it has become the market trend to provide electronic products having lighter, thinner, shorter and smaller characteristics. To fit this market trend, high-performance ICs are developed. From the application of early metal lead frame package technology to current flip chip technology, packaging substrate fabrication has been continuously improved. The invention pertains to improvement on QFN (Quad. Flat No-lead) packaging substrate technology.
QFN semiconductor packaging technology has been intensively used in semiconductor foundries for years for packaging semiconductor products. Several QFN packaging technology based patents have been disclosed. Recently, there are manufacturers to secure pins to the packaging substrate by means of filling up the openings among the pins of the lead frame with an insulative member to form a platform. The platform has one or more chip pads that carry a chip respectively. Passive components or multiple electronic elements may be installed in the platform, increasing space utilization of the packaging substrate.
The aforesaid method of filling up the openings with an insulative member to form a platform greatly increase the usable area of the packaging substrate, however the passive components can only be electrically connected to the adjacent pins, i.e., the aforesaid method does not allow electric connection between two remote pins.